Poration



June 24, 1930. Q R. J. ElSEMAN COMBINED IGNITION TRANSFORMER AND FUEL CONTROL Fild Nov. 11. 1927 $10676 1619 W 061M110 M haw 17 Patented June 24, 1930 UNITED STATES PATENT OFFICE ROBERT J. EISEMAN, 0F CLEVELAND, OHIO, ASSIGNOR 'ro THE x w IGNITION con- .POBATION, or CLEVELAND, 0310, A CORPORATION or OHIO COMBINED IGNITION TRANSFORMER A ND FUEL CONTROL Application filed November 11, 1927.. Serial No. 232,578.

This invention relates to improvements in transformers that are employed to fur nish high voltage current for an igniter, and the invention has to do also with control apparatus, such, for instance, as a valve operator, including an element common to the transformer and the control apparatus.

In my co-pending application, Serial No. 208,941, filed July 28, 1927, there is disclosed a transformer having a core comprising a leg for the primar coil, a leg for the secondary coil and a thir unwound leg of smaller cross section parallel with and close to the leg for the primary coil, this third leg constituting a magnetic shunt which acts as a choke and enables me to reduce the number of turns in the primary andsecon'dary coils of the transformer. In the present invention substantially the same result is obtained with a third leg which is hinged to the main'core of the transformer instead of being integral therewith, and, in addition, the movement of the third leg is utilized to operate a valve or other movable control member. The precise explanation for this phenomenon is not definitely known to me, but as stated in the ap lication above referred to, I am inclined to elieve that it results from the fact that the small third 1e becomes magnetically saturated earlier in t e current cycle than the leg of the secondary coil and that thereafter the magnetic flux in the leg of the secondary coil increases very rapidly, thereby reducing a sharp eak in the flux curve wit a consequent pea in the secondary current running above what would be produced by a flux curve of the sine form.

One of the objects of the invention, therefore, is to reduce the requisite number of turns in the primary and secondarycoils of g a transformer with a resultant important a heavier current in the primary than is.

present when the secondary is out of commission. .This is a valuable feature where the invention is applied to'igniters and fuel valves for gas or oil burners, because it is dangerous to permit a large-volume of combustible mixture to collect in the firebox of a furnace. Hence this feature of my inven tion, which may be briefly described as a no-spark, no-fuel provision, is of considerable importance.

Other objects and features of novelty will appear as I proceed with a description of that embodiment of-the invention, which for the purposes of the present application, I have illustrated in the accompanying drawing, in which Fig. 1 is a somewhat diagrammatic view of a transformer and a fuel valve embodying my invention; and

Fig. 2 is a similar view showing the same apparatus with the addition of a holding coil.

In the drawing, the transformer core, which may be built of laminations in the usual manner, is illustrated as comprising side members 10 and 11 and parallel legs 12 and 13. Primary and secondary coils 14 and 15 are mounted upon the legs 12 and 13, respectively. The side members, 10 and 11 extend somewhat beyond the leg 12, and the member 10 is formed on its extremity to receive the enlarged butt end of a swinging armature or third leg 16, a 1pintle 17 serving to hinge the two parts toget er. The leg 16 is of considerably smaller cross-sectional area than the legs 12 and 13. In practice, I find that the best results are obtained when the leg16 has a crosssectional aera in the neighbor 00d of 31 percent of the cross-sectional area of the legs 12 and 13,.although some deviation from this area either upward or downward ddes not change the result very materially.

As illustrative of a control member which may be operatively connected with the swinging leg 16, I have shown a valve 18 rovided with a stem 19 connected with the eg 16 by means of a ring 20 or the like. A coil spring 21 tends to hold the valve 18 positively upon its seat. Pipes 22 and 23 of a fuel line are shown entering the valve casing 24 and in communication through an angular passage 25 controlled by the valve 18.

The apparatus illustrated in Fi 1 is suitable for use in connection with a uel burner in which continuous electrical ignition is employed. In some burners, however, the i niter is used only to kindle the fire after whic it is turned off. In order to meet the requirements of this type of apparatus Imount on the side member 11 of the core a holdin coil 26 of hi h-resistance wire, as shown in ig. 2. This ho din coil is not strong enough to attract the swinging leg 16 in opposition to the force of spring 21, but is stron enough to hold the same in attracted position without the assistance of coil 14 after the all-metal path for the magnetic flux has been completed. The coil 26 is, of course, independent of the coil 14, and its energization ma be controlled either by a manual switch or y a switch that is automatically actuated in connectionwith the other parts of a burner apparatus, as, for instance, a motor for driving a blower. These parts are not illustrated as the particular means which may be employed for controlling the holding coil 26 is of no moment.

Assuming that the secondary coil 15 is electrically connected with apparatus, such as an igniter for a fuel burner, and that such apparatus is in operative condition so as to draw current from the coil, then the energization of primary coil 14 will momentarily induce particularly strong current im ulses in the secondary coil 15, which are 0 value in an igniter because of burnin off any accumulation of soot from the spar ing points. This momentary extra fat spark occurs when the circuit of coil 14 is first closed because at that time the choking effect produced by the magnetic shunt through the armature 16 is not complete. As soon as the armature is attracted, however, an all-metal path is established through armature 16 and the choking effect is complete. This choking effect holds down the current in coil 14 without recourse to additional turns of wire in the coil for that purpose. Thus I am enabled to reduce to a minimum the turns in coil 14 and to a proportionately greater extent the turns in coil 15. The attraction of armature 16 of course opens valve 18 against the action of spring 21. Should the ignlter be gut of order the flux set up in the core is comparatively li ht and may be connected with the movable leg for actuation thereby.

Having thus described my invention, I claim:

1. A transformer comprisin a core having thereon primary and secon ary windings, said core having a movable le forming a magnetic shunt when the trans ormer is in operation and breakin said shunt when the operation of the trans ormer is discontinued.

2. A transformer comprisin a core having thereon primary and secon ary windings, said core having a movable le forming a magnetic shunt when the trans ormer is in operation and breakin said shunt when the operation of the trans ormer is discontinued, and a movable control element operatively connected with said movable leg.

3. A transformer comprising a core having thereon primary and secondary windings, said core having a movable le forming a magnetic shunt when the trans ormer is in operation and breaking said shunt when the operation of the transformer is discontinued, said movable leg being of less cross sectional area than that portion of the core which carries the principal part of the flux.

4. A transformer comprising a core having three legs, a primary winding on one leg, a secondary winding on another leg, the third leg being unwound and being movable, said third leg in one position formin with the first-named leg a com lete magnetic path and in the other position reaking said path, the magnetic attraction set up by a current in the primary winding serving to move said third leg from the last named position to the first named position.

5. A transformer comprisin a core having thereon primary and secon ary windin s, said core having a hinged leg movable hy electromagnetic force set up in the fixed portion of said core by said primary winding to form a magnetic shunt around a part of said fixed portion of the core.

6. A transformer comprising a core havin two legs for the primary and secondary win ings, said core having a third hinged leg movable by electromagnetic force set up in the primary leg to form a magnetic shunt around a portion of the primary leg, and a movable control element operatively connected with said hinged leg.

7. A transformer comprising a core having two legs for the primary and secondary windings, respectively, said core having a third hinged leg movable by electromagnetic force set up in the primary leg to form with the primary leg a magnetic shunt, and said hinged leg eing of less cross-sectional area than the primary leg and adjacent thereto in attracted position.

v 8. A transformer comprising a core having thereon primary and secondary .windings,

said corehaving a movable leg forming a magnetic shunt when the'transformer is in operation and breaking said shunt when the operation of the transformer is discontinued, a movable control element operatively connected with said movable leg, and a holding coil for maintaining said movable leg in the first named position after the transformer ceases to operate.

9. A transformer for use in connection with an igniter of a fuel burner, comprising a core and primary and secondary coils, and an armature adapted to be attracted to said core when the said primary coil is energized.

10. A transformer for use in connection with an igniter of a fuel burner, comprising a core and primary and secondary coils, and an armature adapted to be attracted to said core when the said primary coil is energized ancll when there is a load on said secondary C01 11. A transformer with an igniter of a fuel burner, comprising a core and primary and secondary coils, an armature adapted to be attracted to said core when the said primary coil is energized and a fuel control element operated by said armature.

12. A transformer for use in connection with an igniter of a fuel burner, comprising a core and primary and secondary coils, an armature adapted to be attracted to said core when the sid primary coil is energized and when there is a load on said secondary coil, and a fuel control element operated by said armature.

In testimony whereof, I hereunto aflix my gnature.

- ROBERT J. EISEMAN.

for use in connection 

